Light guiding apparatus and light source device including the same

ABSTRACT

A light guiding apparatus includes a light guiding apparatus and a second light guide. The first light guide includes a first end-surface, a second end-surface and a side-surface, in which the first end-surface includes a first light incident surface thereon, the second end-surface includes a first light emitting surface thereon, and the side-surface is located between the first end-surface and the second end-surface of the first light guide. The second light guide has a second incident surface and a second light emitting surface connecting the second incident surface, in which at least a partial region of the second light emitting surface is a roughened surface, the second incident surface or the first light emitting surface is a roughened surface, and the second incident surface is corresponding to the first light emitting surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 102202297, filed on Feb. 1, 2013. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND

1. Field of the Utility Model

The present invention generally relates to a light source device, andparticularly, to a light source device having a light guiding apparatus.

2. Description of Related Art

A conventional light source device in a crystal lamp is designedaccording to the tungsten light source at the center of a lampshade.Tungsten-based light-emitting mechanism, however, is verypower-consumed, and it features short life and high power-loss rate.

In recent years, with the good development of the light emitting diode(LED) light source development, another option of the light sourcedevice is available, which can achieve power-saving and othercharacteristics. In the crystal lamp using the conventional light sourceapparatus having the LED, the LED is disposed at an end of a cylinderlight guiding apparatus, where the light is guided by the cylinder lightguiding apparatus to the other end to achieve light transmission effect.

It should be noted that, in the prior art, in order to further increasethe light emission angle of the light source device, the opticalsurfaces of the light guiding apparatus are designed to make the lightbeams reflected to become dispersed. However, merely relying on thedesign of the optical surfaces of the light guiding apparatus fordistributing the light beams has a defect of uneven distribution, whichlikely causes noticeable bright lines occurred when such a light sourcedevice is close to a wall surface, and therefore, it causes a poorvisual effect for a user in the habit of the tungsten-based lightemitting device for long term already.

Thus, how to make a light guiding apparatus uniformly guide out the LEDsource and to increase the visual effect has become an issue to beprimarily resolved in this field today.

SUMMARY OF THE DISCLOSURE

Accordingly, the present invention is directed to a light source device,which has good light uniformity and provides a novel light emittingeffect.

The invention provides a light source device including a light guidingapparatus and a light emitting element. The light guiding apparatusincludes a first light guide and a second light guide. The first lightguide includes a first end-surface, a second end-surface and aside-surface, in which the first end-surface includes a first lightincident surface thereon, the second end-surface includes a first lightemitting surface thereon, and the side-surface is located between thefirst end-surface and the second end-surface of the first light guide.The second light guide has a second incident surface and a second lightemitting surface connecting the second incident surface, in which atleast a partial region of the second light emitting surface is aroughened surface, the second incident surface or the first lightemitting surface is a roughened surface, the second incident surface iscorresponding to the first light emitting surface, and a medium with arefractive index less than the refractive indexes of the first lightguide and the second light guide is located between the second incidentsurface and the first light emitting surface.

In an embodiment of the invention, the side-surface has a first regionand a second region, the first region adjoins the first light incidentsurface, the second region adjoins the first light emitting surface, thenormal at an arbitrary point of the second region of the side-surface isset as a first axis direction, the connection line between the arbitrarypoint and a center of the first light incident surface is set as asecond axis direction, then, the sine of an included angle between thefirst axis direction and the second axis direction is greater than thereciprocal of the refractive index of the first light guide.

In an embodiment of the invention, the area of the second region is atleast five times of the area of the first region.

In an embodiment of the invention, the roughness (Ra) of the first lightemitting surface and the roughened surface of the at least partialregion of the second light emitting surface is at least 0.4 μm.

In an embodiment of the invention, the second incident surface is aroughened surface, and roughness (Ra) of the first light emittingsurface, the second incident surface and the roughened surface of the atleast partial region of the second light emitting surface is at least0.4 μm.

In an embodiment of the invention, the side-surface further includes aplurality of optical planes, and an included angle between any twoadjacent optical planes is unequal to 180°.

In an embodiment of the invention, the first light guide has a firstlocking portion, the second light guide has a second locking portion, apart of the first locking portion is the first light emitting surface,and a part of the second locking portion is the second incident surface.

In an embodiment of the invention, the first light emitting surface hasa recessed portion, at least a part of the second incident surface formsan embedding portion, and the shapes of the recessed portion and theembedding portion are complementary to each other.

In an embodiment of the invention, the embedding portion is a pyramid ora cone.

In an embodiment of the invention, the embedding portion is adhered withthe recessed portion.

In an embodiment of the invention, the first light guide has a firstrefractive index, the second light guide has a second refractive index,the medium between the second incident surface and the first lightemitting surface has a third refractive index, and the differencebetween the third refractive index and the first refractive index or thesecond refractive index is at least 0.5. For example, the medium can beair or adhesive.

In an embodiment of the invention, the side-surface is a smooth surface.

In an embodiment of the invention, the light emitting element isdisposed adjacently to the first light incident surface.

In an embodiment of the invention, the light emitting element includes alight emitting diode (LED).

In an embodiment of the invention, the light source device furtherincludes a lampshade to cover the light guiding apparatus.

Based on the description above, the invention can effectively reduce theproblem of uneven light scattering faced by the prior art through thedesign of the first light guide and the second light guide of the lightguiding apparatus, and thereby the light source device of the inventionhas good light uniformity.

Other objectives, features and advantages of the invention will befurther understood from the further technological features disclosed bythe embodiments of the invention wherein there are shown and describedpreferred embodiments of this invention, simply by way of illustrationof modes best suited to carry out the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded diagram of a light source device according to anembodiment of the invention.

FIG. 2 is a cross-sectional diagram of FIG. 1 along I-I′.

FIGS. 3A to 3C are three-dimensional diagrams of a second light guideaccording to multiple embodiments of the invention.

FIG. 4 is an illumination chart of a light source device according to anembodiment of the invention.

FIG. 5 is a light distribution curve chart of a light source deviceaccording to an embodiment of the invention.

DESCRIPTION OF THE EMBODIMENTS

FIG. 1 is an exploded diagram of a light source device according to anembodiment of the invention and FIG. 2 is a cross-sectional diagram ofFIG. 1 along I-I′. Referring to FIGS. 1 and 2, in the embodiment, alight source device 100 includes a light guiding apparatus 110, a lightemitting element 120 and a lampshade 130. The light guiding apparatus110 includes a first light guide 112 and a second light guide 114. Thefirst light guide 112 includes a first end-surface E1, a secondend-surface E2 and a side-surface 112 c. The first end-surface E1includes a first incident surface 112 a thereon, the second end-surfaceE2 includes a first light emitting surface 112 b thereon, and theside-surface 112 c is located between the first end-surface E1 and thesecond end-surface E2 of the first light guide 112. The second lightguide 114 has a second incident surface 114 a and a second lightemitting surface 114 b connecting the second incident surface 114 a, inwhich at least a partial region of the second light emitting surface 114b is a roughened surface, and the second incident surface 114 a or thefirst light emitting surface 112 b is a roughened surface. The secondincident surface 114 a is disposed correspondingly to the first lightemitting surface 112 b so that the first light emitting surface 112 band the second incident surface 114 a can be optical coupled. Forexample, the second incident surface 114 a is disposed to face the firstlight emitting surface 112 b. There is a medium 116 between the secondincident surface 114 a and the first light emitting surface 112 b, inwhich the refractive index of the medium 116 is less than the refractiveindexes of the first light guide 112 and the second light guide 114. Inaddition, the lampshade 130 is used to cover the light guiding apparatus110, and the light source device 100 can be applied in variousillumination systems such as crystal lamp, showcase light, votive lamp,standing lamp or situation showing light.

In the embodiment, the first light guide 112 and the second light guide114 in the light guiding apparatus 110 can be fabricated by injectionmolding and can have the same materials, for example,polymethylmethacrylate (PMMA) or other light-guidable transparentmaterials.

In the embodiment, the light emitting element 120 is disposed adjacentlyto the first incident surface 112 a, and the light emitting element 120can include LEDs or a linear light source of other types, which theinvention is not limited to.

In the embodiment, the light emitting element 120 provides a light beamL to be transmitted in the first light guide 112. First, the light beamL passing through the first incident surface 112 a enters the firstlight guide 112 and is totally reflected many times by the side-surfaceto be transmitted to the first light emitting surface 112 b. Next, thelight beam L is via the first light emitting surface 112 b and themedium 116, then, the light beam L enters the second light guide 114 viathe second light incident surface 114 a thereafter departs from thesecond light guide 114 via the second light emitting surface 114 b.Wherein, the light beam L is diffused at least twice, once by theroughened surface of the first light emitting surface 112 b or thesecond light emitting surface 114 b, and another once by the roughenedsurface of the second light emitting surface 114 b.

In the embodiment, the refractive index of the first light guide 112 ofthe light guiding apparatus 110 is n1 (first refractive index), therefractive index of the second light guide 114 is n2 (second refractiveindex) and the refractive index of the medium 116 is n3 (thirdrefractive index). The refractive index n_(air) of air is 1.00, in whichthe difference between the refractive index n3 of the medium 116 and therefractive index n1 of the first light guide 112 or the refractive indexn2 of the second light guide 114 can be over 0.5. As a result, after thelight beam L via the roughened surface of the first light emittingsurface 112 b can be effectively diffused so as to advance the lightuniformity of the light source device 100.

Referring to FIG. 1, in the embodiment, the side-surface 112 c of thefirst light guide 112 includes a plurality of optical planes, and theincluded angles between the optical planes are unequal to 180°. Thereby,the user can observe the images from the side-surface 112 c and thesuperposition of light and shadow so as to provide special visualeffects. For example, the side-surface 112 c can include six opticalplanes, which the invention is not limited to.

Referring to FIG. 2, the side-surface 112 c of the first light guide 112can have a first region 112 c 1 and a second region 112 c 2. The firstregion 112 c 1 adjoins the first incident surface 112 a, the secondregion 112 c 2 adjoins the first light emitting surface 112 b, and thearea of the second region 112 c 2 can be at least five times of the areaof the first region 112 c 1.

Assuming the second region 112 c 2 located at the side-surface 112 c hasa point P2 and the point P2 can be located at an arbitrary position ofthe second region 112 c 2. The normal at the point P2 is a first axisdirection AX1, the connection line between the point P2 and the centerP1 of the first incident surface 112 a is a second axis direction AX2,and the included angle between the first axis direction AX1 and thesecond axis direction AX2 is θ.

In the embodiment, when the light beam L come from the center P1 of thefirst incident surface 112 a arrives at the point P2, the incident angleof the light beam L at the time when the light beam L enters the air viathe side-surface 112 c is equal to the included angle θ. It can be seenin FIG. 2 that a refraction angle θ_(light) of the light beam L isbetween 0° and 90°. According to Snell's law (Eq. 1), it can be derivedthat when the sine of the included angle θ is greater than thereciprocal of the refractive index n1 of the first light guide 112, thelight beam L can be transmitted in the first light guide 112 by totalreflection via the side-surface 112 c, which can reduce the intensitydecay of the light beam L during transmitting.

n _(air)×sinθ_(light) =n1×sinθ   (Eq. 1)

In addition, the first incident surface 112 a and the side-surface 112 ccan be smooth surfaces so as to prevent the light beam L from beingdiffused at the first incident surface 112 a and the side-surface 112 cand from loss during the transmitting thereof to the first lightemitting surface 112 b.

In the embodiment, the second light guide 114 has the second incidentsurface 114 a and the second light emitting surface 114 b connecting thesecond incident surface 114 a, in which at least a partial region of thesecond light emitting surface 114 b is a roughened surface so as toimprove the effect of light emitting of the second light emittingsurface 114 b to advance the light uniformity.

In addition, in the embodiment, when the first light emitting surface112 b and the at least partial region of the second light emittingsurface 114 b are roughened surface, the roughness of the roughenedsurface is at least 0.4 m so as to improve the effect of light emittingand advance the light uniformity.

In the embodiment, the second incident surface 114 a can be roughenedsurface, and the roughness (Ra) of the first light emitting surface 112b, the second incident surface 114 a and the roughened surface of the atleast partial region of the second light emitting surface 114 b is atleast 0.4 μm so as to further improve the effect of light emitting andadvance the light uniformity.

In the embodiment, the roughened surface is able to make the light beamdiffused and the roughened surface can be formed by performing etchingprocess, sand-blasting treatment or texturing treatment.

It should be noted that in the embodiment, the first light emittingsurface 112 b has a recessed portion M1 and at least a part of thesecond incident surface 114 a forms an embedding portion M2. Thecross-sectional surface of the recessed portion M1 in the embodimentincludes an inclined surface. In order to effectively avoid undueaggregation of the light beam which is passing through the opticalsurface of the recessed portion M1, the optical surface of the recessedportion M1 can be the above-mentioned roughened surface so as to advancethe uniformity of light distribution. FIGS. 3A-3C are three-dimensionaldiagrams of a second light guide according to multiple embodiments ofthe invention. Referring to FIGS. 3A-3C, the second light emittingsurface 114 b of the second light guide 114 can have any shape, theembedding portion M2 of the second light guide 114 can be a pyramid or acone, and the shape of the recessed portion M1 is corresponding to theshape of the embedding portion M2, i.e., the shapes of the recessedportion M1 and the embedding portion M2 are complementary to each other.Specifically, the space of the recessed portion M1 of the first lightguide 112 is big enough to accommodate the embedding portion M2 of thesecond light guide 114; the shapes of the recessed portion M1 and theembedding portion M2 are corresponding to each other so that theembedding portion M2 can be smoothly embedded into the recessed portionM1; the embedding portion M2 and the recessed portion M1 can beconnected to each other by locking or adhering one another, which theinvention is not limited to.

In the embodiment, the first light guide 112 has a first locking portionO1, the second light guide 114 has a second locking portion O2, a partof the first locking portion O1 is the first light emitting surface 112b, a part of the second locking portion O2 is the second incidentsurface 114 a, and in this way, the first locking portion O1 and thesecond locking portion O2 can lock one another. When the light guidingapparatus 110 is applied in the light source device 100, theabove-mentioned design enables the second light guide 114 and the firstlight guide 112 to be tightly connected to each other without easilybeing separated from each other.

It should be noted that, in the embodiment, at least a part of the lightbeam come from the light emitting device gets total reflection at theside-surface.

In more details, by using the side-surface 112 c to make the light beamL get total reflection and by the design that the first light emittingsurface 112 b has the recessed portion M1, the first light emittingsurface 112 b or the second incident surface 114 a is the roughenedsurface and the second light emitting surface 114 b is the roughenedsurface, the invention helps to make the light beam scattered towardsthe surrounding direction away from a central axis of the light emittingelement 120, and the direction toward where the light emitting device120 is disposed so that the user can observe the scattering light at thesecond light guide 114 and the recessed portion M1 which is like thatthe second light guide 114 is floated in air and a specific visualeffect can be obtained.

FIG. 4 is an illumination chart of a light source device according to anembodiment of the invention. Referring to FIG. 4, it can be seen thatthe light source device of the invention can provide uniform andsymmetrical light distribution, and the displaying light beam has gooduniformity after scattering many times.

FIG. 5 is a light distribution curve chart of a light source deviceaccording to an embodiment of the invention. As shown by FIG. 5, thelight source device of the invention can provide uniform and symmetricallight distribution, and the displaying light beam has good uniformityafter scattering many times.

In summary, the light source device of the invention can effectivelyreduce the uniform beam problem in the prior art and has goodperformance on the visual effect.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentinvention without departing from the scope or spirit of the invention.In view of the foregoing, it is intended that the present inventioncover modifications and variations of this invention provided they fallwithin the scope of the following claims and their equivalents.

What is claimed is:
 1. A light guiding apparatus, comprising: a firstlight guide comprising a first end-surface, a second end-surface and aside-surface, wherein the first end-surface comprises a first lightincident surface thereon, the second end-surface comprises a first lightemitting surface thereon, and the side-surface is located between thefirst end-surface and the second end-surface of the first light guide;and a second light guide having a second incident surface and a secondlight emitting surface connecting the second incident surface, whereinat least a partial region of the second light emitting surface is aroughened surface, the second incident surface or the first lightemitting surface is a roughened surface, the second incident surface iscorresponding to the first light emitting surface, and a medium with arefractive index less than the refractive indexes of the first lightguide and the second light guide is located between the second incidentsurface and the first light emitting surface.
 2. The light guidingapparatus as claimed in claim 1, wherein the side-surface has a firstregion and a second region, the first region adjoins the first lightincident surface, the second region adjoins the first light emittingsurface, a normal at an arbitrary point of the second region of theside-surface is set as a first axis direction, a connection line betweenthe an arbitrary point and a center of the first light incident surfaceis set as a second axis direction, then, sine of an included anglebetween the first axis direction and the second axis direction isgreater than a reciprocal of the refractive index of the first lightguide.
 3. The light guiding apparatus as claimed in claim 2, whereinarea of the second region is at least five times of area of the firstregion.
 4. The light guiding apparatus as claimed in claim 1, wherein aroughness (Ra) of the first light emitting surface and the roughenedsurface of the at least partial region of the second light emittingsurface is at least 0.4 μm.
 5. The light guiding apparatus as claimed inclaim 1, wherein the second incident surface is a roughened surface, anda roughness (Ra) of the first light emitting surface, the secondincident surface and the roughened surface of the at least partialregion of the second light emitting surface is at least 0.4 μm.
 6. Thelight guiding apparatus as claimed in claim 1, wherein the side-surfacefurther comprises a plurality of optical planes, and an included anglebetween any two adjacent optical planes is unequal to 180°.
 7. The lightguiding apparatus as claimed in claim 1, wherein the first light guidehas a first locking portion, the second light guide has a second lockingportion, a part of the first locking portion is the first light emittingsurface, and a part of the second locking portion is the second incidentsurface.
 8. The light guiding apparatus as claimed in claim 1, whereinthe first light emitting surface has a recessed portion, at least a partof the second incident surface forms an embedding portion, and shapes ofthe recessed portion and the embedding portion are complementary to eachother.
 9. The light guiding apparatus as claimed in claim 8, wherein theembedding portion is a pyramid or a cone.
 10. The light guidingapparatus as claimed in claim 8, wherein the embedding portion isadhered with the recessed portion.
 11. The light guiding apparatus asclaimed in claim 1, wherein the first light guide has a first refractiveindex, the second light guide has a second refractive index, the mediumbetween the second incident surface and the first light emitting surfacehas a third refractive index, and difference between the thirdrefractive index and the first refractive index or the second refractiveindex is at least 0.5.
 12. The light guiding apparatus as claimed inclaim 1, wherein the side-surface is a smooth surface.
 13. A lightsource device, comprising: a light guiding apparatus, including: a firstlight guide comprising a first end-surface, a second end-surface and aside-surface, wherein the first end-surface comprises a first lightincident surface thereon, the second end-surface comprises a first lightemitting surface thereon, and the side-surface is located between thefirst end-surface and the second end-surface of the first light guide;and a second light guide having a second incident surface and a secondlight emitting surface connecting the second incident surface, whereinat least a partial region of the second light emitting surface is aroughened surface, the second incident surface or the first lightemitting surface is a roughened surface, the second incident surface iscorresponding to the first light emitting surface, and a medium with arefractive index less than the refractive indexes of the first lightguide and the second light guide is located between the second incidentsurface and the first light emitting surface; and a light emittingelement, wherein the light emitting device is disposed adjacently to thefirst light incident surface.
 14. The light source device as claimed inclaim 13, wherein the light emitting device comprises a light emittingdiode.
 15. The light source device as claimed in claim 13, furthercomprising a lampshade to cover the light guiding apparatus.
 16. Thelight source device as claimed in claim 13, wherein the side-surface ofthe light guiding apparatus has a first region and a second region, thefirst region adjoins the first light incident surface, the second regionadjoins the first light emitting surface, a normal at an arbitrary pointof the second region of the side-surface is set as a first axisdirection, a connection line between the an arbitrary point and a centerof the first light incident surface is set as a second axis direction,then, sine of an included angle between the first axis direction and thesecond axis direction is greater than a reciprocal of the refractiveindex of the first light guide.
 17. The light source device as claimedin claim 16, wherein area of the second region is at least five times ofarea of the first region.
 18. The light source device as claimed inclaim 13, wherein a roughness (Ra) of the first light emitting surfaceand the roughened surface of the at least partial region of the secondlight emitting surface is at least 0.4 μm.
 19. The light source deviceas claimed in claim 13, wherein the first light guide has a firstlocking portion, the second light guide has a second locking portion, apart of the first locking portion is the first light emitting surface,and a part of the second locking portion is the second incident surface.20. The light source device as claimed in claim 13, wherein the firstlight guide has a first refractive index, the second light guide has asecond refractive index, the medium between the second incident surfaceand the first light emitting surface has a third refractive index, anddifference between the third refractive index and the first refractiveindex or the second refractive index is at least 0.5.
 21. The lightsource device as claimed in claim 13, wherein the medium is air oradhesive.